title: Improved susceptibility weighted imaging method using multi-echo acquisition.
abstract: OBJECTIVE
  To introduce novel acquisition and postprocessing approaches for susceptibility weighted imaging (SWI) to remove background field inhomogeneity artifacts in both magnitude and phase data.
  
  
  METHODS
  The proposed method acquires three echoes in a three-dimensional gradient echo (GRE) sequence, with a field compensation gradient (z-shim gradient) applied to the third echo. The artifacts in the magnitude data are compensated by signal estimation from all three echoes. The artifacts in phase signals are removed by modeling the background phase distortions using Gaussians. The method was applied in vivo and compared with conventional SWI.
  
  
  RESULTS
  The method successfully compensates for background field inhomogeneity artifacts in magnitude and phase images, and demonstrated improved SWI images. In particular, vessels in frontal lobe, which were not observed in conventional SWI, were identified in the proposed method.
  
  
  CONCLUSIONS
  The new method improves image quality in SWI by restoring signal in the frontal and temporal regions.
authors.affiliation: Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Electrical Engineering, KAIST, Daejeon, Korea.
authors.forename: Sung Suk
authors.initials: SS
authors.lastname: Oh
authors.forename: Se-Hong
authors.initials: SH
authors.lastname: Oh
authors.forename: Yoonho
authors.initials: Y
authors.lastname: Nam
authors.forename: Dongyeob
authors.initials: D
authors.lastname: Han
authors.forename: Randall B
authors.initials: RB
authors.lastname: Stafford
authors.forename: Jinyoung
authors.initials: J
authors.lastname: Hwang
authors.forename: Dong-Hyun
authors.initials: DH
authors.lastname: Kim
authors.forename: HyunWook
authors.initials: H
authors.lastname: Park
authors.forename: Jongho
authors.initials: J
authors.lastname: Lee
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Gaussian modeling removal; compensation gradient; field inhomogeneity induced artifact; magnetic susceptibility; z-shim